9:15 AM - 9:30 AM
[16a-3A-2] Effect of two-pulse excitation on photo-excited precession of magnetization in (Ga,Mn)As in ultra-short time region
Keywords:ultrafast spin manipulation,spin-photonics
Studying the mechanism of fs-laser-excited precession of magnetization in ferromagnetic (Ga,Mn)As has given us the opportunity of pursuing the mechanism of ultrafast manipulation of ordered spins and new applications in spintronics. In general, photo-induced non-equilibrium states can be classified into three different stages: (i) strong non-equilibrium during the laser pulse width, (ii) thermalization with time scale governed by microscopic process (~ a few ps), and (iii) relaxation into an initial equilibrium with time scale rather governed by macroscopic process (~ ns or longer). This work aims at studying optically those stages by probing the response of ordered spins which are excited by the two pump pulses whose interval Dt is controlled for a wide range between 27 fs and 52 ps.